Controlling and measuring very small quantities of fluid is required in many environments and for many purposes. For example, medical testing procedures as shown in the Johnson et al U.S. Pat. No. 6,983,636 issued in 2006 may require the repetitious application of droplets of identical size. Ink-jet printers require precise control of the flow of very small droplets of ink into their various output openings, and may utilize techniques such as those shown in the Starr U.S. Pat. No. 4,818,706 issued in 1989 or the Shimano U.S. Pat. No. 5,277,333 issued in 1994. In the Meinhart et al U.S. Pat. No. 7,057,198 issued in 2006 a technique is shown for measuring extremely small velocities of a flowing fluid.
The calibration of a gas chromatograph instrument, however, poses a somewhat different problem. Gas chromatography instruments identify the nature and smell of a gas by measuring the quantities of its different constituents. From time to time such an instrument may require calibration or re-calibration, due to various factors that have changed either within the instrument itself or in its environment. It has been a common calibration practice to inject a droplet of a known compound into the inlet or throat of the chromatograph instrument and compare the response of the instrument with a known standard. The Kovat Index of the injected droplet may be utilized in completing the comparison.
The calibration of a gas chromatography machine has often been accomplished by manual use of a syringe to inject the test droplet into the inlet or throat of the chromatography instrument. When a syringe is used there are disadvantages. Syringes are fragile and are dangerous to use because of the sharp needle. Syringes are also easy to contaminate and require special handling techniques. It is also difficult for an operator to control the syringe for accurately aiming the droplet into the inlet or throat of the machine. Mis-direction of the droplet may cause contamination of the precision chromatography instrument and thus adversely affect the accuracy of its subsequent measurements.